The Sigma 15mm f2.8 is a more regarded lens than the Canon counterpart and it's still available. The Canon 8-15mm f4 L lens is very sweet and makes a great FX lens. Zoom bursts and zoom swirls will never be the same again! The zoom has slightly less CA, but it's still quite strong. I guess correcting a full frame 180 degree AOV is pretty difficult, but it can be defished with some pretty horrific drops in quality. I think the zoom is a tad sharper, but there is really very little between them. The zoom is more flexible and offers more options, but like all fisheye lenses....best used in moderation and infrequently. I like mine a lot, it's a lot of fun but it's not a lens I use often. In terms of distortion....it's a fisheye....yes it's a distorted view....it's supposed to be....lol!

... but like all fisheye lenses....best used in moderation and infrequently. I like mine a lot, it's a lot of fun but it's not a lens I use often. In terms of distortion....it's a fisheye....yes it's a distorted view....it's supposed to be....lol!

I've learned that if I shoot with the camera leveled and pointed at the horizon, people like the wide effect without minding the distortion too much.

The masses aren't likely to have the $3,000+ needed to get the telephoto goodnes you are proposing.

Oh, I don't know. Two and a half years ago, I blanched at the thought of $1,000+ lenses, now I own two. If a new 100-400 comes in at $2,500-$3,000 I'm sure there will be many takers, myself included. Particularly if it has 4-stop (or better) IS, and improved IQ.

Of course, there would be many more if the price were in the $2,000-$2,500 range...

Don't forget, Canon's next new option "up" from a hypothetical $3,000 100-400LII, the 300mm f/2.8L II, costs over $7,000...

I want a lens that does not yet exist. I would like a 24-135 f1.4-f2.8 L with IS. Preferably less than 800 grams; black, not white; and using a 77mm filter.

That would be my perfect walkabout lens (the the perfect kit lens). The 24-105L is really nice, but I wish it were faster. I've finally come to appreciate the advantage of the faster lens with the 5D3 AF system.

I also like the idea of a modest-range walkaround lens. Longer reach than 70mm, but not going crazy like the 28-300mm to reduce distortion and keep size/weight reasonable. However, I think this one sabotages its chances in two key areas:

1) I'd be shocked to see a zoom with that kind of range open up to f1.4. Even f2.0 would probably be fantasy. Consider the 28-300mm which has f3.5-5.6, or the 28-135mm which also has f3.5-5.6. I think we'd be lucky to get f2.8-3.5 over a 24-135mm range. Throw in IS and there goes your weight criteria.

2) If they sold a great-quality lens in that range, we'd have no need to buy any other bright primes or even the 24-70mm f2.8 ii! The kings of marketing and product-differentiation would never allow it. That reasoning explains the good-but-not-great IQ of the 24-105mm.